feat(web): provide a directory listing via s3-revproxy

Thanks to Jade Lovelace who built all this machinery for Lix initially.

Signed-off-by: Raito Bezarius <masterancpp@gmail.com>

hosts/public01/default.nix

@@ -10,7 +10,7 @@
   networking.domain = "infra.forkos.org";
 
   bagel.sysadmin.enable = true;
-  # Buildbot is proxied.
+  # Newsletter is proxied.
   bagel.raito.v6-proxy-awareness.enable = true;
   bagel.newsletter = {
     enable = true;
@@ -27,6 +27,17 @@
     };
   };
 
+  bagel.services.s3-revproxy = {
+    enable = true;
+    domain = "forkos.org";
+    s3.apiUrl = "s3.delroth.net";
+    targets = {
+      channels = "bagel-channels";
+      releases = "bagel-releases";
+      channel-scripts-test = "bagel-channel-scripts-test";
+    };
+  };
+
   i18n.defaultLocale = "en_US.UTF-8";
 
   system.stateVersion = "24.05";

overlays/default.nix

@@ -3,5 +3,6 @@
     iusb-spoof = final.callPackage ./iusb-spoof.nix {};
     u-root = final.callPackage ./u-root {};
     pyroscope = final.callPackage ./pyroscope {};
+    s3-revproxy = final.callPackage ./s3-revproxy {};
   })
 ]

overlays/s3-revproxy/default.nix

@@ -0,0 +1,39 @@
+# Originally written by Jade Lovelace for Lix.
+{ lib, buildGoModule, fetchFromGitHub }:
+buildGoModule rec {
+  pname = "s3-revproxy";
+  version = "4.15.0";
+
+  src = fetchFromGitHub {
+    owner = "oxyno-zeta";
+    repo = "s3-proxy";
+    rev = "v${version}";
+    hash = "sha256-q0cfAo8Uz7wtKljmSDaJ320bjg2yXydvvxubAsMKzbc=";
+  };
+
+  vendorHash = "sha256-dOwNQtTfOCQcjgNBV/FeWdwbW9xi1OK5YD7PBPPDKOQ=";
+
+  ldflags = [
+    "-X github.com/oxyno-zeta/s3-proxy/pkg/s3-proxy/version.Version=${version}"
+    "-X github.com/oxyno-zeta/s3-proxy/pkg/s3-proxy/version.Metadata="
+  ];
+
+  postPatch = ''
+    # Refer to the included templates in the package instead of cwd-relative
+    sed -i "s#Path = \"templates/#Path = \"$out/share/s3-revproxy/templates/#" pkg/s3-proxy/config/config.go
+  '';
+
+  postInstall = ''
+    mkdir -p $out/share/s3-revproxy
+    cp -r templates/ $out/share/s3-revproxy/templates
+  '';
+
+  meta = {
+    description = "S3 Reverse Proxy with GET, PUT and DELETE methods and authentication (OpenID Connect and Basic Auth)";
+    homepage = "https://oxyno-zeta.github.io/s3-proxy";
+    # hm, not having a maintainers entry is kind of inconvenient
+    maintainers = [ ];
+    licenses = lib.licenses.asl20;
+    mainProgram = "s3-proxy";
+  };
+}

services/default.nix

@@ -11,5 +11,6 @@
     ./baremetal-builder
     ./buildbot
     ./newsletter
+    ./s3-revproxy
   ];
 }

services/s3-revproxy/default.nix

@@ -0,0 +1,131 @@
+# Originally written by Jade Lovelace for Lix.
+# Adapted for ForkOS.
+{ lib, config, ... }:
+let
+  inherit (lib) mkEnableOption mkIf types mkOption mapAttrs mapAttrs' nameValuePair;
+  cfg = config.bagel.services.s3-revproxy;
+  s3RevproxyPort = 10652;
+  mkTarget = { name, bucket ? name }: {
+    mount = {
+      host = "${name}.${cfg.domain}";
+      path = [ "/" ];
+    };
+    actions.GET = {
+      enabled = true;
+      config = {
+        # e.g. /2.90 will 404, so it will redirect to /2.90/ if it is a directory
+        redirectWithTrailingSlashForNotFoundFile = true;
+        indexDocument = "index.html";
+      };
+    };
+
+    bucket = {
+      name = bucket;
+      region = "garage";
+      s3Endpoint = "https://${cfg.s3.apiUrl}";
+      credentials = {
+        accessKey.env = "AWS_ACCESS_KEY_ID";
+        secretKey.env = "AWS_SECRET_KEY";
+      };
+    };
+  };
+  # Makes a subdomain that gets proxied through s3-proxy to provide directory
+  # listings and reasonable 404 pages.
+  # This is not used on cache, since there a directory listing for cache is a
+  # liability at best.
+  mkProxiedSubdomain = subdomain: {
+    enableACME = true;
+    forceSSL = true;
+    locations."/" = {
+      recommendedProxySettings = true;
+      proxyPass = "http://127.0.0.1:${toString s3RevproxyPort}/";
+    };
+  };
+in
+{
+  options.bagel.services.s3-revproxy = {
+    enable = mkEnableOption "a S3 reverse proxy";
+
+    domain = mkOption {
+      type = types.str;
+    };
+
+    s3 = {
+      apiUrl = mkOption {
+        type = types.str;
+        description = "An URL to the S3 API";
+      };
+    };
+
+    targets = mkOption {
+      type = types.attrsOf types.str;
+      description = ''
+        A mapping between a nice name and a bucket name.
+      '';
+    };
+  };
+
+  imports = [
+    ./module.nix
+  ];
+
+  config = mkIf cfg.enable {
+    age.secrets.s3-revproxy-api-keys.file = ../../secrets/s3-revproxy-api-keys.age;
+    # For each target, generate an entry that passes it to the s3-revproxy.
+    services.nginx.virtualHosts = mapAttrs' (subdomain: _: nameValuePair "${subdomain}.${cfg.domain}" (mkProxiedSubdomain subdomain)) cfg.targets;
+    # this solves garage supporting neither anonymous access nor automatic
+    # directory indexing by simply ignoring garage's web server and replacing it
+    # with overengineered golang instead.
+    services.s3-revproxy = {
+      enable = true;
+      settings = {
+        templates = {
+          helpers = [ ./s3-revproxy-templates/_helpers.tpl ];
+          notFoundError = {
+            headers = {
+              "Content-Type" = "{{ template \"main.headers.contentType\" . }}";
+            };
+            status = "404";
+          };
+          folderList = {
+            path = ./s3-revproxy-templates/folder-list.tpl;
+            headers = {
+              "Content-Type" = "{{ template \"main.headers.contentType\" . }}";
+            };
+            # empty s3 directories are not real and cannot hurt you.
+            # due to redirectWithTrailingSlashForNotFoundFile, garbage file names
+            # get redirected as folders, which then appear as empty, yielding
+            # poor UX.
+            status = ''
+              {{- if eq (len .Entries) 0 -}}
+                404
+              {{- else -}}
+                200
+              {{- end -}}
+            '';
+          };
+        };
+        /* For metrics and debugging (e.g. pulling the config)
+        internalServer = {
+          listenAddr = "127.0.0.1";
+          port = 1337;
+        };
+        */
+        server = {
+          listenAddr = "127.0.0.1";
+          port = s3RevproxyPort;
+
+          # it's going right into nginx, so no point
+          compress.enabled = false;
+          cors = {
+            enabled = true;
+            allowMethods = [ "GET" ];
+            allowOrigins = [ "*" ];
+          };
+        };
+        targets = mapAttrs (name: bucket: mkTarget { inherit name bucket; }) cfg.targets;
+      };
+      environmentFile = config.age.secrets.s3-revproxy-api-keys.path;
+    };
+  };
+}

services/s3-revproxy/module.nix

@@ -0,0 +1,69 @@
+# Originally, written by Jade Lovelace for Lix.
+{ config, pkgs, lib, ... }:
+let cfg = config.services.s3-revproxy;
+  settingsGenerator = pkgs.formats.yaml {};
+  # Needs to be in a directory, so we might as well implement autoreload, why not!
+  configFile = settingsGenerator.generate "config.yaml" cfg.settings;
+
+  inherit (lib) types;
+in
+{
+  options.services.s3-revproxy = {
+    enable = lib.mkEnableOption "s3 reverse proxy";
+    package = lib.mkPackageOption pkgs "s3-revproxy" {};
+    settings = lib.mkOption {
+      default = { };
+      type = settingsGenerator.type;
+      description = ''
+        Settings to use for the service. See the documentation at https://oxyno-zeta.github.io/s3-proxy/configuration/structure/
+      '';
+    };
+
+    environmentFile = lib.mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      description = ''
+        Environment file to use for s3-revproxy.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment.etc."s3-revproxy/config.yaml".source = configFile;
+    systemd.services.s3-revproxy = {
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        ExecStart = "${lib.getExe cfg.package} --config /etc/s3-revproxy";
+
+        DynamicUser = true;
+        CapabilityBoundingSet = "";
+        NoNewPrivileges = true;
+        PrivateTmp = true;
+        PrivateUsers = true;
+        PrivateDevices = true;
+        ProtectHome = true;
+        ProtectClock = true;
+        ProtectProc = "noaccess";
+        ProcSubset = "pid";
+        UMask = "0077";
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectControlGroups = true;
+        ProtectHostname = true;
+        RestrictSUIDSGID = true;
+        RestrictRealtime = true;
+        RestrictNamespaces = true;
+        LockPersonality = true;
+        RemoveIPC = true;
+        SystemCallFilter = [ "@system-service" "~@privileged" ];
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        MemoryDenyWriteExecute = true;
+        SystemCallArchitectures = "native";
+
+        EnvironmentFile = lib.optionals (cfg.environmentFile != null) [ cfg.environmentFile ];
+      };
+    };
+  };
+}

services/s3-revproxy/s3-revproxy-templates/_helpers.tpl

@@ -0,0 +1,37 @@
+{{/* SPDX-License-Identifier: Apache-2.0 */}}
+{{/* SPDX-FileCopyrightText: 2024 s3-proxy contributors */}}
+
+{{- /* This function will allow to get user identifier. */ -}}
+{{- define "main.userIdentifier" -}}
+{{- if .User -}}
+{{- .User.GetIdentifier -}}
+{{- end -}}
+{{- end -}}
+
+
+{{- /* This function will allow to get the content type header from "Accept" header */ -}}
+{{- define "main.headers.contentType" -}}
+{{- if contains "application/json" (.Request.Header.Get "Accept") -}}
+application/json; charset=utf-8
+{{- else -}}
+text/html; charset=utf-8
+{{- end -}}
+{{- end -}}
+
+{{- /* This will forge the json output of an error */ -}}
+{{- define "main.body.errorJsonBody" -}}
+{"error": {{ .Error.Error | toJson }}}
+{{- end -}}
+
+{{- define "notFoundErrorBody" -}}
+  {{- if contains "application/json" (.Request.Header.Get "Accept") -}}
+  {{ template "main.body.errorJsonBody" . }}
+  {{- else -}}
+  <!DOCTYPE html>
+  <html>
+    <body>
+      <h1>Not Found {{ .Request.URL.Path }}</h1>
+    </body>
+  </html>
+  {{- end -}}
+{{- end -}}

services/s3-revproxy/s3-revproxy-templates/folder-list.tpl

@@ -0,0 +1,52 @@
+{{/* SPDX-License-Identifier: Apache-2.0 */}}
+{{/* SPDX-FileCopyrightText: 2024 s3-proxy contributors */}}
+{{- $root := . -}}
+{{- if eq (len .Entries) 0 -}}
+  {{- include "notFoundErrorBody" . -}}
+{{- else -}}
+
+{{- if contains "application/json" (.Request.Header.Get "Accept") -}}
+[
+  {{- $maxLen := len $root.Entries -}}
+  {{- range $index, $entry := $root.Entries -}}
+  {"name": {{ $entry.Name | toJson -}}
+    ,"etag": {{ $entry.ETag | toJson -}}
+    ,"type": {{ $entry.Type | toJson -}}
+    ,"size": {{ $entry.Size | toJson -}}
+    ,"path": {{ $entry.Path | toJson -}}
+    ,"lastModified": {{ $entry.LastModified | date "2006-01-02T15:04:05Z07:00" | toJson -}}
+  }{{- if ne $index (sub $maxLen 1) -}},{{- end -}}
+  {{- end -}}
+]
+{{- else -}}
+  <!DOCTYPE html>
+  <html>
+    <body>
+      <h1>Index of {{ .Request.URL.Path }}</h1>
+      <table style="width:100%">
+          <thead>
+              <tr>
+                  <th style="border-right:1px solid black;text-align:start">Entry</th>
+                  <th style="border-right:1px solid black;text-align:start">Size</th>
+                  <th style="border-right:1px solid black;text-align:start">Last modified</th>
+              </tr>
+          </thead>
+          <tbody style="border-top:1px solid black">
+            <tr>
+              <td style="border-right:1px solid black;padding: 0 5px"><a href="..">..</a></td>
+              <td style="border-right:1px solid black;padding: 0 5px"> - </td>
+              <td style="padding: 0 5px"> - </td>
+            </tr>
+          {{- range .Entries }}
+            <tr>
+                <td style="border-right:1px solid black;padding: 0 5px"><a href="{{ .Path }}">{{ .Name }}</a></td>
+                <td style="border-right:1px solid black;padding: 0 5px">{{- if eq .Type "FOLDER" -}} - {{- else -}}{{ .Size | humanSize }}{{- end -}}</td>
+                <td style="padding: 0 5px">{{ .LastModified }}</td>
+            </tr>
+          {{- end }}
+          </tbody>
+      </table>
+    </body>
+  </html>
+  {{- end -}}
+{{- end -}}

services/s3-revproxy/s3-revproxy-templates/not-found-error.tpl

@@ -0,0 +1,3 @@
+{{/* SPDX-License-Identifier: Apache-2.0 */}}
+{{/* SPDX-FileCopyrightText: 2024 s3-proxy contributors */}}
+{{- include "notFoundErrorBody" . -}}